From 582c7f25aaa992a3cc8618f6332d553dc5b39ada Mon Sep 17 00:00:00 2001
From: wirawan <wirawan>
Date: Fri, 19 Feb 2010 18:41:28 +0000
Subject: [PATCH] * Generic generator module.

---
 generators.py | 43 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644 generators.py

diff --git a/generators.py b/generators.py
new file mode 100644
index 0000000..f5c66c5
--- /dev/null
+++ b/generators.py
@@ -0,0 +1,43 @@
+# -*- python -*-
+#
+# $Id: generators.py,v 1.1 2010-02-19 18:41:28 wirawan Exp $
+#
+# Created: 20100218
+# Wirawan Purwanto
+#
+"""
+
+Various generators
+
+"""
+
+def all_combinations(seq):
+  """Generates stream of tuples containing all possible
+  combinations of items (where order matters).
+
+  This is useful e.g. for generating all possible indices for a multidimensional
+  array.
+  Example:
+  >>> for i in all_combinations((xrange(4), xrange(3))): print i
+  (0, 0)
+  (1, 0)
+  (2, 0)
+  (3, 0)
+  (0, 1)
+  (1, 1)
+  (2, 1)
+  (3, 1)
+  (0, 2)
+  (1, 2)
+  (2, 2)
+  (3, 2)
+
+  """
+  if len(seq) <= 1:
+    for i in seq[0]:
+      yield (i,)
+  else:
+    for s1 in all_combinations(seq[1:]):
+      for s0 in seq[0]:
+        yield (s0,) + s1
+